T80 (8080) running its first program in Cyclone II

T80 core is a free opensource Z80 and 8080 core available on opencores.org.

This is a record of my early steps in adopting it. A little program starts preloaded in ROM at 0x0000, copies itself into the upper area at 0x8000, jumps over there and keeps looping forever.

Green leds latch processor status word pumped out in the beginning of each cycle: leftmost bit, 7, is MEMR, 5th is M1.

Red leds, in this configuration, show latched values being written to memory. At first you can see bits of the program being copied, then it's alternating 0xF0/0x0F (see code). Two upper leds are DBIN and SYNC outputs of the 8080.

7-segment leds show address bus.

;; the code!

org 0

lxi d, 8000
lxi h, program
lxi b, theend-program
copy:
mov a, m
stax d
inx h
inx d
dcx b
mov a, c
ora b
jnz copy

mvi a, 0f
mov b, a
lxi h, 8000
pchl


; will be at 8000

program:
loopx:
mov a, b
sta 0ffff
cma
mov b, a
lxi d, 4000
nop
nop
nop
nop
pchl

theend:
nop

Category:

Howto & Style

Tags:

• FPGA
• i8080
• z80
• Altera
• Cyclone

[Elamin008]

Do you need special tool (aka programmer ) to program it or it all done though usb cable ?

[svofski]

@Elamin008 the board has everything and ready to use, you program it through usb cable.

[mrblah125]

That is so cool!!

honestly :D

[DL3CE]

@faffaflunkie

At least there was 8085 equipment on Mars .. (rover of Pathfinder).

[faffaflunkie]

Although the chip is an obvious copy of the Intel 8080, a power hog (Z-80/8080 power supplies can burn screwdrivers in half) and is obsolete by about a dozen technological generations, the Z-80 is a chip that just can't be killed. Just watch, there will be Z-80 based equipment on Mars one day.

[DL3CE]

@faffaflunkie Thats the TM34B1 .. more popular is the U880 which was produced in eastern Germany (DDR) which was part of the soviet union back than. You can use it as an plug-in replacement .. if it fits into the socket, the eastern ICs often used an 2.5mm pin pitch instead of that evil capitalistic 0.1inch (2.54mm) pin pitch (since the mid of the 80ties they changed gradually to 0.1" because they started to export their (cheaper) chips into the west).

[MrMerlinss]

This is nice and informative

[brickman409]

@kirbyyasha

you are only person i understood in the comments lol

[kirbyyasha]

0:39 - BOOb

[svofski]

@faffaflunkie of course they do, but there are many people who are self-taught, too.

[faffaflunkie]

@svofski So they can get the real ones over there. Do they teach you progamming?